What is system injection kit?

Plastic Gundam model kits are manufactured by Bandai in Japan which has an exclusive license in manufacturing and marketing them around the world, the first of them being sold in 1980 in Japan. The models are typical of Plastic model; frames of injection-molded Polystyrene (PS) parts which must be cut out of the frame before assembly. The majority of post-1990 models have snap-fit parts, with models prior to that requiring an adhesive such as plastic cement. Plastic Gundam models kits are typically supplied with stickers and sometimes decals to apply extra colors and markings as seen in popular media such as TV shows, movies, manga or video games. Smaller or lower-grade kits often require paint to give the model a finished appearance, due to color discrepancies.

The kits range in different scales with the most popular scales being: 1:550 , 1:220, 1:144, 1:100 and 1:60, and more recently the 1:35 (UC HardGraph) line. Generally in real world terms, kits range from 4~5 inches for small-scale models, 6 to 8 inches for mid-scale models, and 12 inches for big-scale models, although these sizes vary from model to model. With a few exceptions, all currently produced kits bear grade ratings that give a good idea about their final quality. The following lists the most well-known and common categories with humanoid designs (very roughly) in their order of quality, from lowest to highest.

Please note that other categories, such as EX Model, do exist. Additionally, Bandai often produces limited-run kits for special events such as JAFCON or C3 conventions. These have different packaging, and usually only differ from their common counterparts in that they are metal-plated or made of translucent plastic.